The present invention comprises a new and distinct cultivar of calla lily, botanically known as Zantedeschia sprengeri and hereinafter referred to by the cultivar name ‘Denver’.
‘Denver’ is a product of a planned breeding program, which had the objective of creating Zantedeschia hybrids for pot flower production in a wide range of colors with a large, classic flower shape. The breeding program began in 1989, and the new cultivar is a seedling selected from the crossing of a Zantedeschia sprengeri selection referred to as Z020045-422 (female parent, unpatented) with a Zantedeschia sprengeri selection referred to as ‘Garnet Glow’ (male parent, unpatented). ‘Denver’ was selected in 2008 by the inventor in 't Zand, The Netherlands as one flowering plant within the progeny of the stated cross.
The first act of asexual reproduction of ‘Denver’ by tissue culture was performed by the inventor in September of 2011 in 't Zand, The Netherlands. Subsequent asexual reproductions by tissue culture at the same location have demonstrated that the combination of characteristics as herein disclosed for the new cultivar are retained and reproduced true to type through successive generations of asexual reproduction.
The following observations, measurements and comparisons describe plants grown in 14 cm pots in 't Zand, The Netherlands under greenhouse conditions, which approximate those generally used in horticultural practice. Color references are made to The R.H.S. Colour Chart of The Royal Horticultural Society of London, except where general color terms of ordinary significance are used.
The present invention has not been evaluated under all possible environmental conditions. The phenotype may vary with variations in environment without a change in the genotype of the plant.
The following traits have been repeatedly observed and determined to be basic characteristics of ‘Denver’ which, in combination, distinguish this calla lily as a new and distinct cultivar:                1. Large, pink and white-colored spathe, with the white color of between White Group RHS 155A to 155B being mostly present on the inner, lower spathe surface;        2. Large throat spot in spathe having a color between Purple Group RHS N79A and 79A; and        3. High inflorescence production.        
Further, when compared to calla lily plant named ‘Samur’ (unpatented), ‘Samur’ has an upper surface spathe color that varies between Red-Purple Group RHS 68B and 68D, whereas the upper surface spathe color of ‘Denver’ varies between Red Group RHS 50C and Red-Purple Group RHS 60A.
Table 1 provides similarities and differences of ‘Denver’ to its parents, Zantedeschia sprengeri selections Z020045-422 and ‘Garnet Glow’.
TABLE 1‘Denver’SimilaritiesDifferencesZ020045-422Number of inflorescencesSpathe colorLeaf colorLeaf shapeSpathe shape‘Garnet Glow’Leaf shapeSpathe colorNumber of inflorescencesSpathe shape